Lenze PLC Designer PLC Designer (R3-1) - Manual (Page 566)

L-force | PLC Designer
General Editors
564 DMS 4.1 EN 03/2011 TD29
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13.1.2 Definition of a SoftMotion CAM disk
A CAM disk prescribes a functional dependency of one parameter (Slave) on another
(Master). The dependence can be expressed via a continuous mapping from the range
of master values to slave values. More precisely, after subdividing the master-axis in
appropriate intervals the graph of this mapping can be represented either by a straight
line or by a quintic polynomial (degree 5) on each of these intervals.
Graph of a CAM disc: the master values are assigned to the horizontal axis, the slave
values to the vertical one.
Abb. 303 Example of CAM disk graph
In the example, the master values range between 0 and 360. This range is divided into
three intervals:
• the
first one on the left: [0, 140]
• the second one in the middle: [140, 280]
• the third one on the right: [280, 360]
On the first and third interval the mapping is linear and therefore represented by a
straight line. Hence, its first derivative (that is its gradient)
is constant, its higher derivatives are equal to zero.
On the second interval the mapping is a polynomial of degree 5. Hence, its first
derivative is a polynomial of degree 4, its second derivative
(that is its curvature) a polynomial of degree 3, its third derivative a polynomial of
degree 2 (and so on...).
If you think of the mapping as motion of the slave in dependence of the position of the
master, its first derivative accords to the velocity of the slave, its second derivative to
the slave acceleration.